If we go by general agreed moral, which could be called one definition of objective, or if we went with the golden rule, that was around before Jesus, Jesus said it and quite a few people after him, including Kant and other people with huge influence on the modern western world, if we take all that into account, we could think of what it says, which is that you should not do upon others which you do not want to be done to yourself, which in this case obviously means that you do not want to get murdered, therefore you should not murder other people, of course this does, as the only exception, not apply to suicidal people, though they usually have quite a few other problems than the question if it is okay for them to murder someone, but if you take them into account, and do not say that the exception proves the rule, you would still go with that if they were healthy, they would not want to get murdered, so they also should not murder someone, therefore Kant is still proven right even with that exception, which in fact proves that murder is in most objective and subjective viewpoints bad.